Built-up hollow field-weldable structural steel length



June 26, 1962 N. R. ABBERLY BUILT-UP HOLLOW FIELD-WELDABLE STRUCTURALSTEEL LENGTH Filed Sept. 12, 1960 INVENTDR United States Patent G3,040,846 BUILT-UP HOLLOW FIELD-WELDABLE STRUCTURAL STEEL LENGTHNicholas Rippen Abberly, 4018 Worth St., Dallas 10, Tex. Filed Sept. 12,1960, Ser. No. 55,501 8 Claims. (Cl. 189-24) This invention relates tosteel lengths that contributorily constitute all types and sizes ofstructures, both earthanchored and movable, particularly the skeletonsof tier structures, as well as relating to lengths that do not form apart of an inclusive structure, namely, poles. Excepting wherequalified, the comprehensive expression, general lengths, includingtherefore poles as well, has been adopted herein.

The application of the invention is limited to lengths designed foraifixment in the field by welding; field welding is of course notassociable with full heat-treatment, for which a furnace large enough tohouse the inclusive structure is used.

A salient ultimate aim consists in providing general lengths, respectingevery contemplated ratio of length to weight or transverse dimensions,or of Weight thereto, with a structure-derived degree of strength thatexceeds that attained in all comparable other general lengths. Theexpression, structure-derived, refers to the fact that, so far asconcerns invention aspects, the augmentation in strength derives fromgeometric and afiixing and not from metallurgic innovations.

The salient possibilitating aim consists in providing, as part of eachgeneral length, an outside member or members, termed, shielding,constituted of relatively soft metal and which is at least limitedlyfield-weldable, and an inside member or members, termed, coring, ofrelatively hard metal, there being between the shielding and the coring,airspaces designed to obstruct the passage of outside welding heat fromthe shielding to the coring in an amount sufiicient to damage thelatter.

The term, coring, a coined one, designates, in a given said length, thesingle core or plurality of core elements. A coring is simple when,transversely regarded, there is a single core element. It is complexwhen, transversely regarded, it consists of a plurality of coreelements. Such a plurality is not to be confused with a longitudinallydisposed plurality of simple cores. The herein adopted symbols for them,derived from said expressions, are SC and CC.

The shielding is preferably of machinable metal in the sense that holescan be drilled in it in the field with port able tools mounting cobaltdrills and not necessarily carbide drills (because of the ditficulty ofestablishing a rigid relationship between the tool and the drilledobject), altho carbide-tipped drills should be alternatively employable(instead of the cobalt drills). The expression, fieldweldable, will bedefined elsewhere herein.

Admissible in all embodiments is every conceivable ratio between thelong dimensions of the shielding and the coring. Coring constitutes, inevery embodiment, at least an auxiliary strength member. Shielding, atone extreme, serves as a substantially nonstrength member with the solefunction for it that of an afiixing means, and, at the other extreme,constitutes the main strength member, the one or more longitudinallydistributed elongated but abbreviated cores supplying extra strength atcritical points, otherwise expressed, locally. One embodiment of thislast mentioned arrangement would be in a pole where the shieldingconstitutes the major strength member or main pole body. In such a pole,the coring consists of one or more abbreviated cores, with at least oneof them stiffening the pole at the most highly stressed point, theanchoring zone. Like the traditional inside connectors of the liner3,040,846 Patented June 26, 1962 type, one or more cores can so serve atthe junctures between successive sections of poles too high to beintegral.

To describe the invention in a few Words, the inventionincorporatingstructural hollow built-up steel length includes at least one firstlength-long integral member. It may be either an outside or an insideone. Additionally included is a least one elongated integral othermember, which too may be an inside or an outside one, depending on whichthe first member is, and it too may be a length long one or anabbreviated one. The outside member is of a relatively soft steel and istransversely tensionally stressed in its coring girthing state. Theshielding girths the coring in such a relation thereto that they adjoinone another transversely discontinuously. By this is meant there is aplurality of transversely successive mutually sep arated airspaces and,alternating with them, a plurality of transversely successive mutuallyseparated pairs of contact-zone portions, the two in each pair beingintegral respective portions of the coring and the shielding. In eachcontact zone, the two in each pair pressurally engage one another attheir mutually faying surfaces with the maximally extensive areaspossible in order to minimize the ratio of unit pressure value to unitarea value, so that shielding and coring of extreme contrast betweentheir respective hardnesses can, if desired, be incorporated into thelength. Generally, the shielding will be also more machinable and morefield-weldable than the coring. Said air spaces serve to bar thetransmission of most of the welding heat (which is applied in the fieldto the shielding) to the coring. What welding heat does reach the coringis of an amount insufficient to deleteriously alter the grain structureof and thereby weaken or embrittle the coring. The described relationfacilitates the fabrication of steel lengths that, notwithstandingfield-weldability, particularly when both the shielding and the coringare length-long, are stronger than any comparable, equallyfield-weldable steel lengths ever made, by virtue of the fact that themajor strength member, the coring, can be constituted of a steel of suchhardness that its incorporation into structures could not have been atall realistically contemplated before the advent of this invention.

Since ultimate tensile strength in steels is closely related tohardness, and, in the case of those heat-treated, almost perfectly,hardness numbers are used for comparing strengths. Detailed treatment ofthis matter is presented elsewhere.

Research in ferrous metallurgy will, perhaps soon, record advancesleading to lifting present standards to still higher levels. An alreadysolidly established boron-andless-than-one-percent-nickel limitedlyfield-weldable steel is available with 120 kips ultimate and kips yieldstrength. The qualification refers to the fact that thefield-weldability can be had only with plural beads. Preheating andpostheating, being only moderately beneficial, are not needed. Topredict the appearance of a singlepass-field-weldable,less-than-one-percent-nickel, morethan-IZO-IOO-kips steel with noaugmented cost for the other alloys, calls perhaps for a great measureof optimism. A conservative guess pictures, in the shielding, saidIZO-IOO-kips steel improved to the point of beingsinglepass-field-weldable, and, in the coring, any suitable one of anumber of already available, altogether nonfield weldable, extremelyhard steels of the kind never incorporated into construction. Pendingthe appearance of said improved steel, the rule is laid down that, inall invention-incorporating lengths, the coring steel ultimate strengthexceeds that of the shileding by at least '50 kips. This would seem tobe reasonable in the light of the state of the art at the time thisinvention was conceived and this patent applied for. It is based on theuse of said l20-l00-k-ips steel (unimproved) in the coring, and of 3 theASTM A7 steel, with its 70 kips ultimate strength, in the shielding.

Because the hardness numbers in the carbide-ball Brinell systemcorrespond, within three and mostly within two and many by less than onepercent, to kips values doubled, they have been selected for indirectlydesignating shielding and coring ultimate strengths. In allinvention-incorporating lengths the Brinell carbide-ball hardness numberof the coring steel exceeds that of the shielding steel by 100.

The term, shopwelded, refers only to shopwelded coring elements, thewelding being followed by full heattreatment in a completely enclosingfurnace. The shopwelding of shielding, if any, is not accorded mention;it is not essentially related to the invention. Of the conceivablespecies two have been chosen for illustration and description herein. Inthe first the coring is simple. In the second it is complex. In both thecross-sectional form is circular. Either species is associable with apole of constant diameter, with one that is straighttapered, and withone that is stepped-tapered, these three forms being of course notspecies-defining factors. In the accompanying drawing, to which nowrefer for a complete understanding of the invention, the two species areshown in association with only the two tapered forms.

FIGURE 1 is an elevation view of a straight-tapered pole of either thefirst or the second species.

FIGURE 2 is an elevation view of a stepped-tapered pole of either thefirst or the second species.

FIGURE 3 is a one-fourth symmetrical cross-sectional view in the plane3-3 in FIGURE 1 and in the plane 3-3 in FIGURE 2, assuming that the twoare of the first species.

FIGURE 4 is a one-fourth symmetrical cross-sectional view in the plane(4-4) in FIGURE 1 and in the plane (44) in FIGURE 2, assuming that thetwo are poles of the second species.

FIGURE 5 is a fragmentary elevation view of a fragment circumscribed at5 in FIGURE 1 and of a fragment circumscribed at 5 in FIGURE 2, assumingthat the two are poles of the second species.

In FIGURE 1, the pole body rests on the base, 11, and, at the top, bearsthe cap 12.

In FIGURE 2, the pole body rests on the base 13, and, at the top, bearsthe cap 14.

In FIGURE 3 can be seen the internally helically ribbed, relativelysoft, field-weldable shielding, 15, and the externally helicallythreaded or ribbed, relatively hard, simple coring (core element), 16,which jointly constitute the greater part of the pole body in eitherFIGURE 1 or FIGURE 2 when it is one of the first species.

In FIGURE 4 can be seen the internally helically ribbed, relativelysoft, field-weldable shielding, 17, and the relatively hard, complexcoring 18-19, which consists of the core element 18 and the core element19. These three elements jointly constitute the greater part of the polebody in either FIGURE 1 or FIGURE 2 when it is one of the secondspecies.

Plain-surface core element 18 interveningly adjoins shielding 17 and theexternally helically ribbed core element 19.

In the first species the helical direction of the shielding is oppositeto that of the coring. In the second species the helical direction ofthe shielding is recommendedly opposite to that of the ribbed coreelement. Because of the mutual opposition of the helical directions, thedirect mutual engagement of shielding ribs and coring ribs in the firstspecies (and the indirect mutual engagement or radially projectedintersection of the helical directions in the second species) is atpoints. These points coact to produce a faired state of the shielding(and of the coring) surface. Should the ribs in one element be parallelwith those in the other, the pressure exerted on one another would tendto produce unsightly and also functionally undesirable ridges andhollows.

To fabricate and assemble the poles, plates that have been hot rolledwith lengthwise extending ribs would be sheared on the bias in a mannerwhereby the rib direction is obliquely angular to the plate edges, forexample, at an angle of forty-five degrees. Each now obliquely ribbedplate is buttwelded to constitute a tubular member. In the case of atapered pole of the straight type a recommended procedure consists inheating the shielding to a plastic-working temperature, and the coringmade a tapering one at either ambient temperature or 1 freezingtemperature while the shielding is initially a constant-diameter tube.The two are very quickly forced into intercngagement, during which thereis effected not only strength integration of the two members but thecoring, functioning like a die imposes its own tapering form on theshielding. In the case of complex coring the two core elements arehandled as if one was a coring and the other a shielding, whereupon thesubassembly of the two is handled like a simple coring and assembledwith the shielding in the manner described.

The pole body in FIGURE 2 can be an integral one but the stepped-taperedform actually is conditioned by the sectionalizing of the pole becauseof being too long for shipping as an integral pole. The connector at thebase and those at the two junctures are represented by dotted lines.

llclaim:

1. A structural length consisting in the main of these components: anelongated tubular coring of relatively hard metal; a theretointerference-fitted, elongated, tubular shielding of relaively softmetal and girthing at least a part of the coring and having, on theinner surface thereof, a plurality of mutually parallel and helicallydisposed shielding ridges which are in pressural engagement with thecoring, there being constituted, between the shielding and the coring, aplurality of airspaces.

2. A structural length as described in claim 1, said coring consistingof a single core element having, on the outer surface thereof, aplurality of mutually parallel and helically disposed coring ridges inpressural engagement with the therewith intersecting shielding ridges,the helical directions of the two said pluralities of ridges beingopposite one another.

3. A structural length as described in claim 1, said coring consistingof two core elements, one being a tubular, innermost first core elementhaving, on the outer surface thereof, a plurality of mutually paralleland helically disposed coring ridges, the other being a tubular,intervening second core element having a smooth inner and a smooth outersurface respectively pressurally engaging said coring ridges and saidshielding ridges.

4. A structural length as described in claim 1, said coring consistingof two core elements, one being a tubular, innermost first core elementhaving, on the outer surface thereof, a plurality of mutually paralleland helically disposed coring ridges, the other being a tubular,intervening, second core element having a smooth inner and a smoothouter surface respectively pressurally engaging said coring ridges andsaid shielding ridges, the helical directions of the two saidpluralities of ridges being opposite one another.

5. A structural length as described in claim 1, the Brinell carbide-ballhardness number for the coring exceeding that for the shielding by atleast one hundred.

6. A structural length as described in claim 1, said coring consistingof a single core element having, on the outer surface thereof, aplurality of mutually parallel and helically disposed coring ridges inpressural engagement with the therewith intersecting shielding ridges,the helical directions of the. twosaid pluralities of ridges beingopposite one another, the Brinell carbide-ball hardness number for saidcore element exceeding that for the shielding by at least one hundred.

7. A structural length as described in claim 1, said coring consistingof two core elements, one a tubular innermost first core element having,on the outer surface thereof, a plurality of mutually parallel andhelioally disposed coring ridges, the other a tubular intervening secondcore element having a smooth inner and a smooth outer surfacerespectively pressurally engaging said coring ridges and said shieldingridges, the Brinell carbide-ball hardness number for at least one of thetwo core elements exceeding that for the shielding by at least onehundred.

8. A structural length as described in claim 1, said coring consistingof two core elements, one a tubular innermost first core element having,on the outer surface thereof, a plurality of mutually parallel andhelically disposed coring ridges, the other a tubular intervening secondcore element having a smooth inner and a smooth outer surfacerespectively pressurally engaging said coring ridges and said shieldingridges, the helical direotions of the two said pluralities of ridgesbeing opposite one another, the Brinell carbide-ball hardness number forat least one of the two core elements exceeding that for the shieldingby at least one hundred.

References Cited in the file of this patent UNITED STATES PATENTS426,561 Dithridge Apr. 29, 1890 514,665 Serrell Feb. 13, 1894 1,179,696Canada Apr. 18, 1916 2,960,114- Hinde Nov. 15, 1960

